The present invention relates to a perforating tool, especially for perforating steel bands and the like used to form hose clamps and the like. My earlier U.S. Pat. Nos. 3,523,337 and 3,579,754 disclosed clamping devices which included steel bands having a plurality of regularly spaced apertures formed therein. These apertures serve for the purpose of accommodating barb members on a tightening device of the clamp, whereby the band could be tightened and maintained in a tightened condition on a base. FIG. 1 of this application schematically depicts the clamping band of my invention disclosed in U.S. Pat. No. 3,579,754.
For mass produced clamps with perforated bands, it is quite efficient and economical to perforate the bands on large fixed perforating machines. It has also been contemplated to produce a perforated band in long strips which can later be cut up into smaller portions to form individual clamps. With this last-mentioned arrangement, it is possible to tailor make bands to the desired end usage, provided one has the locking apparatus such as shown in my above-noted patents.
However, there occurs situations in usage of this type of clamp, wherein it would be more advantageous if the clamping band included apertures only along a certain portion of the length thereof. For example, it will be readily understood that the strength of the band could be impaired by the inclusion of apertures around the entire periphery, especially if there are any inconsistencies in the construction of the band and/or the construction of the apertures along the length thereof. Also, if portions of the length of the band are to perform any type of sealing function or housing function, it would be desirable not to have apertures therealong.
Another important advantage of having apertures only at the end portion for engagement with the clamping devices is that a much stronger clamping effect can be obtained. If the band is perforated along its length (circumference of the band), the rubber or other material being clamped is pressed outwardly into the apertures so as to act as a brake preventing circumferential adjustment of the clamp portions, with consequent reduction in the clamping effect of the clamp. With the present invention, it is possible to selectively perforate the band only at the end portions, to accommodate the clamping devices, and thereby avoid the just-noted disadvantageous effects of hose material being pressed radially outwardly into the perforations along the circumference of the band.
There are also instances where it would be more economical to stock a small supply of unperforated band material, for use in making perforated aperture clamps of the above-described type, as well as for other usages. Heretofore, it has been impractical for small maintenance shops, gas stations, farms and the like to utilize stock flat band material for making hose clamps and the type on a small unit volume because of the expense and complexity of the band perforating equipment required. Especially in instances where remote field application of hose clamps and the like are required, such as in emergency automobile and truck repairs where it is uneconomical, and, in some instances practically impossible, to transport the vehicle back to a large repair shop, it would be desirable to have a portable tool which could facilitate construction of hose clamps, such as radiator hose clamps, to whatever desired configuration required.
Although makeshift perforating apparatus could be used to form perforated bands, such as hammer and punch arrangements, there are many drawbacks to the known perforating devices with respect to ease of operation, operator safety, reliability, repeatability of the desired aperture pattern, and the like.
Accordingly, the present invention contemplates filling the above-noted needs and overcoming the above-noted disadvantages of prior arrangements by providing a manually operable perforating tool which is easy to operate, maximizes safety for the operator, assures proper alignment and positioning of the apertures being made, and provides for simple interchangeability of the perforating tool parts. The interchangeability of tool parts is especially advantageous for the use of interchangeable tool dies to accommodate changes of the aperture size and geometric configuration, without requiring a new basic tool.
According to preferred embodiments contemplated by the present invention, a tool is provided which includes a first movable lever, a second movable lever, first and second perforating tool means supported at said levers and being movable with respect to one another, said first tool means including a perforating plunger movable therewith, said second tool means including guide means for guiding movement of said plunger, and band support means carried by one of said tool means and including a support surface for supporting a band during perforating movement of an end portion of said plunger through said band during movement of said first and second levers with respect to one another. According to a further feature of preferred embodiments of the invention, the tool means are constructed as rigid tool blocks pivotally supported at the levers for relative movement with respect to the levers in such a manner that pivotal movement of the levers effect a relative linear movement of the plunger and female perforating tool support die which supports the band during perforation operations. It is further contemplated for preferred embodiments of the invention that the levers be plier-like levers operable by one hand of an operator, whereby the tool can be held and operated with one hand while the other hand places the band strip in position on the tool for forming the apertures.
According to another feature of preferred embodiments of the invention, band stop pin means are provided for indexing and positioning the band with respect to the perforating plunger, whereby a repetitive reliable pattern of apertures can be formed in the band. In preferred embodiments, the stop pin is configured to have a diameter corresponding to the width of the plunger, whereby the band is maintained in a fixed correct axial position once the plunger is in an already formed aperture. In preferred embodiments, the stop pin is spring biased into position so as to accommodate movement of the band through the tool to the desired positions for forming apertures.
According to other important features of the present invention, preferred emobidments are constructed so as to accommodate disassembly of the tool and an exchange of the tool die blocks, without requiring disassembly of the basic plier-like lever construction. In preferred embodiments, the perforating plunger is carried by a first rigid tool block which is pivotally connected to a first lever of the tool at a pivot axis spaced from the common lever pivot axis, while the female die portion, as well as the plunger guide portion and support surface for the band are formed at a second rigid tool block, which is pivotally connected to the other of the levers.
Preferred embodiments also include guide pin means at the levers engageable in open guide slots of the respective tool block that are pivotally connected to the other of the levers, so as to axially guide and control the movement of the tool blocks during the pivotal movement of the levers. It is also contemplated in preferred embodiments to include enlargements at the common lever pivot axis engageable in semi-cylindrical recesses of the tool blocks for aiding and guiding the movement of the tool blocks during perforating operations, as well as also permitting ready disassembly of the tool blocks.
Preferred embodiments of the invention are constructed so as to accommodate switching to between right and left hand operation of the perforating tool, merely by removing a detachable support for the band stop pin and attaching it to the other side of the female tool block.
Further, according to preferred embodiments of the invention, the pivotal connection of the tool blocks to the plier-like levers is at a position spaced oppositely of the lever pivot axis with respect to the handles of the tool by a predetermined distance assuring a large mechanical advantage or increase of the manual force applied at the levers when transferred to the tool blocks.
In preferred embodiments of the invention, spring means are provided intermediate the lever handles for holding the same in spaced relationship corresponding to a non-perforating position of the tool, whereby one need only squeeze the levers together to perform a perforating operation.
It is also contemplated by the present invention to include embodiments with differently configured male and female die blocks, so that the same plier-like tool can be used for different sizes and shapes of band apertures, as desired.
In preferred embodiments, the perforating plunger is carried by one of the tool blocks by way of a simple T-shaped recess, whereby disassembly of the plunger with respect to said tool block can be accomplished merely by lifting the plunger laterally of the recess. In this manner, the plunger can be readily exchanged and removed for sharpening, replacement and the like. Also, with this configuration, the tool block for the plunger need not be exchanged, but merely the plunger itself need be exchanged when the female die opening is changed for accommodating a different aperture configuration.
These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a single embodiment in accordance with the present invention.